As mobile telephones, smart phones, tablet personal computers (PCs), and other mobile devices have had more functions, inductors (coil parts) used in these devices are desirable to be more compact in recent years.
A thin-film inductor is known as an inductor having a structure that may make the inductor compact. To form a thin-film inductor, a coil pattern is formed on a substrate by forming a conductive pattern on the substrate with a conductor such as a copper material and then growing the conductive pattern by plating. In this structure, the cross-sectional area of the coil pattern is increased by plating, reducing its resistance. As a result, the current capacity of the coil may be increased, enabling the device to be more efficient. A related technology is disclosed in, for example, Japanese Laid-open Patent Publication No. 8-213740.